Super-directional light emission and emission reversal from micro cavity arrays

Optical microdisk cavities with certain asymmetric shapes are known to possess unidirectional far-field emission properties. Here, we investigate arrays of these dielectric microresonators with respect to their emission properties resulting from the coherent behaviour of the coupled constituents. This approach is inspired by electronic mesoscopic physics where the additional interference effects are known to enhance the properties of the individual system. As an example we study the linear arrangement of nominally identical Lima\c{c}on-shaped cavities and find mostly an increase of the portion of directional emitted light while its angular spread is largely diminished from 20 degrees for the single cavity to about 3 degrees for a linear array of 10 Lima\c{c}on resonators, in fair agreement with a simple array model. Moreover, by varying the inter-cavity distance we observe windows of reversion of the emission directionality and super-directionality that can be interesting for applications. We introduce a generalized array factor model that takes the coupling into account.Comment: 5 pages, 5 figures, supplemental materia

A Benchmark Environment Motivated by Industrial Control Problems

In the research area of reinforcement learning (RL), frequently novel and promising methods are developed and introduced to the RL community. However, although many researchers are keen to apply their methods on real-world problems, implementing such methods in real industry environments often is a frustrating and tedious process. Generally, academic research groups have only limited access to real industrial data and applications. For this reason, new methods are usually developed, evaluated and compared by using artificial software benchmarks. On one hand, these benchmarks are designed to provide interpretable RL training scenarios and detailed insight into the learning process of the method on hand. On the other hand, they usually do not share much similarity with industrial real-world applications. For this reason we used our industry experience to design a benchmark which bridges the gap between freely available, documented, and motivated artificial benchmarks and properties of real industrial problems. The resulting industrial benchmark (IB) has been made publicly available to the RL community by publishing its Java and Python code, including an OpenAI Gym wrapper, on Github. In this paper we motivate and describe in detail the IB's dynamics and identify prototypic experimental settings that capture common situations in real-world industry control problems

A Benchmark Environment Motivated by Industrial Control Problems

In the research area of reinforcement learning (RL), frequently novel and promising methods are developed and introduced to the RL community. However, although many researchers are keen to apply their methods on real-world problems, implementing such methods in real industry environments often is a frustrating and tedious process. Generally, academic research groups have only limited access to real industrial data and applications. For this reason, new methods are usually developed, evaluated and compared by using artificial software benchmarks. On one hand, these benchmarks are designed to provide interpretable RL training scenarios and detailed insight into the learning process of the method on hand. On the other hand, they usually do not share much similarity with industrial real-world applications. For this reason we used our industry experience to design a benchmark which bridges the gap between freely available, documented, and motivated artificial benchmarks and properties of real industrial problems. The resulting industrial benchmark (IB) has been made publicly available to the RL community by publishing its Java and Python code, including an OpenAI Gym wrapper, on Github. In this paper we motivate and describe in detail the IB's dynamics and identify prototypic experimental settings that capture common situations in real-world industry control problems

Optische Systeme im Phasenraumbild

Optical Microcavities are established model systems for non-linear dynamics. This motivates their description in phase space using Husimi-Functions, which give insight into the main radiation directions and the mode distribution at the dielectric interface. In this work, we generalize the application of Husimi-Functions to coupled microcavity systems

Geometric Guidance for the Deployment of Elastic Geodesic Grids

Elastic gridshells are advanced free-form structures enabling curved target shapes and material-efficient large spans. This paper focuses on a novel type of gridshells recently proposed employing a scissor-like deployment mechanism. While recent form-finding advancements have produced fascinating outcomes, a significant challenge arises when architecturally implementing such mechanisms: for the realization of real-world structures, professional FEA is necessary. However, performing Finite Element simulations of these structures proves surprisingly complex due to the requirement of simulating the deployment -- a task nearly unachievable using uninformed approaches. Therefore, geometric guidance of the highly elastic gridshells while simulating the expansion is essential. Present solutions to this predicament primarily involve rudimentary trial-and-error methods, suitable only for the most basic shapes. We propose a solution involving the provision of geometric guidance via sequences of linear displacements synchronized with a universal time parameter. When applied to chosen positions, this allows for multi-step gridshell deployment and successfully avoids undesirable buckling issues. We conclude with successful demonstrations of our method, anticipating our work to pave the way for further quantitative explorations of these intriguing structures.Comment: journal preprint, 10 pages including appendix, 13 figure

Tajixanthonhydrat und dessen Verwendung zur Behandlung von Tumorerkrankungen

Es werden Tajixanthonhydrat sowie Tajixanthonhydrat-Derivate der allgemeinen Formel I $F1 beschrieben sowie ein Verfahren zu ihrer Herstellung. Tajixanthonhydrat besitzt u. a. eine ausgeprägte Biofilm-inhibierende Wirkung gegen Staphylococcus epidermidis